200104 Response to GMDSS Alarms

Response to GMDSS Alarms
Report No. 200104

I feel that I should respond to MARS 200059 GMDSS Alarms. I have a great deal of sympathy with the writer, unfortunately I believe he is attributing blame to the wrong people. Most of those of us who attend the IMO COMSAR conferences are ex-Deck Officers like himself, and have had many years at sea usually in command; in my case, 34 years as a watchkeeping officer in the RN of which 28 were as a Communications Officer.

In the "good old days", yes, Sparks did come to the Bridge with a Distress Message. He did, however, distract the OOW from his duties in order to find out where the Distress was. True, it probably wasn't for over an hour, but distract him, he did. So the distraction factor hasn't changed.

We, who attend IMO regularly, and those of us, who work for IMO on the GMDSS on a daily basis, are all too aware of the problems of False Distress Alerts and spurious Distress Relays. We are actively trying to find a means of eliminating both. A large body of us would like to see an end to HF DSC as it is the prime offender for long range False Distress Alerts and the greatest distracter and irritant of Bridge Watchkeepers.

Your correspondent lays the blame for these unnecessary relays on the watchkeepers on the ships. This may be true in a few cases, but in most it is due to a design fault. Almost all first generation DSC equipment was designed to send an AUTOMATIC relay if it picked up a Distress Alert. All newer equipment requires a manual input i.e. the watchkeeper needs to hear the Distress, listen out for a Coast Station/RCC to acknowledge and then, and only then, when there is no response, should he send his relay. I suspect that this was drilled into your correspondent when he did his GOC course. The problem lies in the fact that the old equipment complies with the original GMDSS equipment specification so IMO is powerless to insist that owners replace them. As a result we are stuck with the problem until all this old equipment is replaced in the course of time.

If HF DSC had been limited only to vessels in Sea Area A4, which are few and far between, the problem would have been containable. If the sole means of Distress Alerting in Sea Area A3 were INMARSAT-C, disregarding the use of an EPIRB, the number of False Distress Alerts/Relays would be significantly less. Since it is now cheaper to buy an INMARSAT-C, than it is to buy modern HF DSC equipment, I am amazed that so many proliferate. It may be that a lot of equipment combines MF and HF DSC - this is a particular problem with US made equipment - so that in order to meet the GMDSS equipment fit for Sea Area A2, owners find themselves saddled with an HF DSC which they would rather not have. On this equipment, if you send a Distress Alert on 2187.5kHz, the equipment also sends it automatically on 4,6, 8, 12 and 16 kHz, which compounds the problem considerably. This problem is further exacerbated by the special deals offered by shipbuilders. If you accept a package put together by the builder, the vessel is considerably cheaper - change anything, even the communications fit, and the price escalates significantly.

In mid-ocean, such distractions are unlikely to be critical, but when approaching harbour or a restricted waterway such as the Dover or Singapore Straits and the ship has gone to stand-by, it is a different matter. The only Distress Alert that the vessel is likely to be interested in at that time is one received on VHF DSC, which might be close-by. It would, I would venture to suggest, be prudent in this situation, to switch off HF/MF DSC on going to stand-by. I cannot see a Master turning his vessel round to assist a vessel, possibly thousands of miles away, when he is committed to entering harbour or transiting a VTIS. In this way the irritating distractions are removed at the most critical time.

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